Gliding boards, such as snowboards, snow skis, water skis, and the like, are well known in the art and in the sporting world. Generally, a rider is securely held to the gliding board with a binding that connects to the gliding board and generally to the rider's feet or boots. Various types of bindings have been developed to allow the user to engage the gliding board. The present disclosure is described with reference to the currently preferred snowboard binding embodiments, although the present invention may readily be adapted for other gliding board applications.
Prior art snowboard binding systems are generally categorized as either strap (or conventional) bindings that typically include a rigid highback against which the back side of the boot is placed and one or more straps that secure the boot to the binding, or step-in bindings that typically utilize one or more strapless engagement members into which the rider can step to lock the boot into the binding. For example, the strapless engagement members may engage metal cleats integrated into the sole of the boot. Strap bindings are the earlier and most popular type of snowboard binding and are adjustable, secure, and comfortable. Step-in bindings allow the user to more easily engage and disengage from the snowboard.
Both strap bindings and step-in bindings usually include a highback ankle support that extends upwardly from the snowboard and is positioned to overlie the back of the user's boot. The back ankle portion of the rider's boot abuts against a curved forward surface of the highback, essentially providing leverage by which the rider can control the snowboard's heel edge. Alpine riders who need to perform high speed turns generally prefer a taller and stiffer highback for greater edge control, whereas freestyle riders generally prefer a shorter highback for better flexibility.
The maximum forward lean angle is herein defined to be the angle that the highback forms with the snowboard (or base plate of the binding) when the highback is pivoted to its rearward stop, and is illustrated as the angle MFL in FIG. 1C. The maximum forward lean angle is important to the feel and control of the snowboard. In prior art bindings the maximum forward lean angle is typically adjusted by the rider using a mechanical stop that is slidably disposed on the highback and abuts the top edge of the heel loop. A rider will slide and lock the block to provide a particular maximum forward lean angle that may be selected based on a variety of factors, including the type of snowboarding to be undertaken, the slope conditions, and the like.
Of course, the rider's ankles are important to controlling the snowboard and, in particular, the angular orientation of the snowboard relative to the snow about all three axes, and especially about the longitudinal axis. The human ankle is a complex system of flexible connections between the lower leg and foot that can be characterized as three separate joints. The first joint is the dorsiflexion ankle joint formed between the lower ends of the tibia and fibula and the uppermost bone in the foot, the talus. This joint allows movement of the foot in dorsiflexion/plantar flexion (i.e., toe up and down). The second joint is the subtalar joint between the two largest foot bones, the talus and calcaneus, which allows inversion and eversion movement of the foot. The subtaler joint is located below the ankle joint. Finally, the transverse tarsal joint is composed of the talus and calcaneus bones on the back side, and the navicular and cuboid bones on the front side. The subtaler joint permits abduction (toe out) and adduction (toe in) movement.
The adjustability of the maximum forward lean angle MFL requires that the highback portion of the binding be adjustable in the direction of dorsiflexion/plantar flexion of the rider's ankle. It is therefore desirable for the highback portion to pivot about an axis that is approximately coaxial with the rider's axis for dorsiflexion of the ankle joint. However, because the dorsiflexion ankle joint is located higher than the other joints in the ankle, snowboard binding designers have had to compromise in order not to interfere with the other ankle joints, and the highback portion of prior art bindings is generally constructed to pivot about an axis that is well below the dorsiflexion ankle joint. The result is that the highback is not optimally positioned with respect to the rider's ankle over the design range of settings for the maximum forward lean angle.
As discussed above, in conventional bindings the maximum forward lean angle of the highback is adjusted by setting the position of a block member that is slidably attached to the back highback; see for example, U.S. Patent Publication No. 2006/0237920, which is hereby incorporated herein in its entirety. The block member is slidable along a back side of the highback and can be locked into place such that when the highback is at the desired maximum forward lean angle the block member abuts the heel loop, preventing any further rearward pivot.
In prior highback bindings, for example, the binding disclosed in copending U.S. patent application Ser. No. 11/114,290, which is hereby incorporated by reference in its entirety, a repositionable and lockable block member is disposed on the rear face of the highback. The block member engages or abuts a U-shaped heel loop that extends behind the highback to limit the rearward pivot of the highback. This rearward limit allows the user to apply a torque to the snowboard, for example, to aggressively dig the rearward edge of the snowboard into the snow to achieve a desired maneuver. The slidable and lockable block member permits the user to selectively adjust the maximum forward lean angle by suitably positioning the block member. The block member provides an adjustable, positive, well-defined stop to the rearward pivot of the highback.
However, the block member is relatively bulky, adds expense to the binding, and limits the designer's options when designing the highback. A need exists for a simpler mechanism for limiting the maximum forward lean angle for the highback portion of a snowboard binding, while still providing an adjustable, positive stop.
Moreover, highback flexibility is an important design aspect in snowboard bindings, and affects the performance and feel of the binding. Eliminating the need for a sliding block mechanism would allow a designer to provide a more even flexure pattern in the highback that is best suited for snowboarding performance and comfort.